library(plotly)
zc <-matrix(nrow = 180, ncol = 180)
for (i in c(1:180)) {
    for (j in c(1:180)) {
        zc[i,j] = sin((i-1)/90*pi)*cos((j-1)/90*pi)
    }
}
plot_ly(z = ~zc, type = "surface")